Abstract

The most important information for source localization is oceanographic knowledge supplied to a powerful machine that numerically computes acoustic Green's functions rapidly and accurately. By this means the distorting effects of the oceanic medium and its boundaries can be removed, thereby rendering the ocean transparent. Then targets can be detected, localized, and classified at low S/N ratios as though they were moving in free space, leading to the result there is “no place to hide.” As an illustration of this approach, we discuss in detail the solution of the problem of passive narrow‐band acoustic localization (an instance of the inverse source problem) following the pioneering work of Bucker [J. Acoust. Soc. Am. 59, 368–373 (1976)], in which beamforming was made obsolescent. Using the PESOGEN (Parabolic Equation SOlution GENerator) computer system [J. Acoust. Soc. Am. Suppl. 1 75, S26 (1984)] and an algorithm based on the generalized principle of reciprocity, we have demonstrated theoretically that targets can be accurately and reliably localized at long ranges and low S/N ratios using sparse configurations of sensors.